nvdimm: do not show pfn_seed for non pmem regions

This simple change hides pfn_seed attribute for non pmem
regions because they don't support pfn anyway.
Signed-off-by: NDmitry V. Krivenok <krivenok.dmitry@gmail.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

drivers/nvdimm/region_devs.c

@@ -406,6 +406,9 @@ static umode_t region_visible(struct kobject *kobj, struct attribute *a, int n)
 	struct nd_interleave_set *nd_set = nd_region->nd_set;
 	int type = nd_region_to_nstype(nd_region);
 
+	if (!is_nd_pmem(dev) && a == &dev_attr_pfn_seed.attr)
+		return 0;
+
 	if (a != &dev_attr_set_cookie.attr
 			&& a != &dev_attr_available_size.attr)
 		return a->mode;